E-Posters-10052

10052_Routzong

Pdf Summary

The study investigated the contribution of the superficial perineal structures during the second stage of labor. The researchers aimed to determine if including these structures in a simulation of childbirth would affect the stretch ratios measured in the pubovisceral muscles (PVM) and perineal body (PB).<br /><br />Previous models of vaginal childbirth have typically included the levator ani muscles but ignored the superficial perineal structures such as the bulbocavernosus muscle (BCM), ischiocavernosus muscle (ICM), deep transverse perinei muscles (DTPM), and superficial transverse perinei muscles (STPM).<br /><br />Using a finite element model, the researchers simulated the second stage of labor. The maternal anatomy was segmented from cryosection images of a female cadaver. The pelvis and sacrum were rigid bodies, while the fetal head was modeled as rigid but allowed to simulate passage through the birth canal. All muscles were treated as nearly incompressible, isotropic, neo-Hookean, 3D continuum. Connective tissue was simulated as two-force structures with user-defined springs.<br /><br />The results showed that the model with superficial perineal structures had higher stretch ratios in the PVM and PB compared to the model without these structures. The right PVM experienced higher stretch ratios than the left. In the PB, the model with superficial perineal structures predicted values 51% larger than the model without them.<br /><br />This study suggests that excluding superficial perineal structures overestimates stretch ratios in the PVM and underestimates stretches in the PB during the second stage of labor. Therefore, it is important to consider these structures in simulations of childbirth as their effect is significant. Additionally, the model with superficial perineal structures provides a better overall representation of maternal geometry in response to a crowning fetal head.<br /><br />The study acknowledges its limitations but suggests that future research should focus on the inclusion of superficial perineal structures in simulations of the second stage of labor.

Keywords

superficial perineal structures

second stage of labor

simulation of childbirth

stretch ratios

pubovisceral muscles

perineal body

levator ani muscles

bulbocavernosus muscle

ischiocavernosus muscle

deep transverse perinei muscles